• Nuclear Engineering and Technology
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• v.46 no.4
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• pp.547-556
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• 2014

Korea expects a shortage in storage capacity for spent fuels at reactor sites. Therefore, a need for more metal and/or concrete casks for storage systems is anticipated for either the reactor site or away from the reactor for interim storage. For the purpose of interim storage and transportation, a dual purpose metal cask that can load 21 spent fuel assemblies is being developed by Korea Radioactive Waste Management Corporation (KRMC) in Korea. At first the gamma and neutron flux for the design basis fuel were determined assuming in-core environment (the temperature, pressure, etc. of the moderator, boron, cladding, $UO_2$ pellets) in which the design basis fuel is loaded, as input data. The evaluation simulated burnup up to 45,000 MWD/MTU and decay during ten years of cooling using the SAS2H/OGIGEN-S module of the SCALE5.1 system. The results from the source term evaluation were used as input data for the final shielding evaluation utilizing the MCNP Code, which yielded the effective dose rate. The design of the cask is based on the safety requirements for normal storage conditions under 10 CFR Part 72. A radiation shielding analysis of the metal storage cask optimized for loading 21 design basis fuels was performed for two cases; one for a single cask and the other for a $2{\times}10$ cask array. For the single cask, dose rates at the external surface of the metal cask, 1m and 2m away from the cask surface, were evaluated. For the $2{\times}10$ cask array, dose rates at the center point of the array and at the center of the casks' height were evaluated. The results of the shielding analysis for the single cask show that dose rates were considerably higher at the lower side (from the bottom of the cask to the bottom of the neutron shielding) of the cask, at over 2mSv/hr at the external surface of the cask. However, this is not considered to be a significant issue since additional shielding will be installed at the storage facility. The shielding analysis results for the $2{\times}10$ cask array showed exponential decrease with distance off the sources. The controlled area boundary was calculated to be approximately 280m from the array, with a dose rate of 25mrem/yr. Actual dose rates within the controlled area boundary will be lower than 25mrem/yr, due to the decay of radioactivity of spent fuel in storage.

• Computers and Concrete
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• v.17 no.2
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• pp.281-294
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• 2016

The increased awareness of electromagnetic wave hazards has prompted studies on electromagnetic shielding using conductive materials in the construction industry. Previous studies have explored the effects of the types of conductive materials and their mix proportions on the electromagnetic shielding performance; however, there has been insufficient research on the effect of the geometry of the conductive materials on the electromagnetic shielding performance. Therefore, in this study, the dependence of the electromagnetic shielding performance on the cross-sectional geometry, diameter and length of fibers was investigated. The results showed that the electromagnetic shielding performance improved when the fiber length increased or the diameter decreased, but the effect of the cross-sectional geometry of the fibers was smaller than the effect of the fiber spacing factor.

• Composites Research
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• v.29 no.4
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• pp.138-144
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• 2016

Recently, electromagnetic interference (EMI) shielding materials have been extensively developed and significantly considered to protect electronic systems from harmful electromagnetic waves. Although, metal-based materials show high electrical conductivity and EMI shielding effectiveness, they have several challenging problems such as high density and corrosion. Carbon-based materials have been acclaimed as alternative EMI materials due to light weight, high mechanical properties, resistance to corrosion and excellent electrical conductivity. Here, we introduce 1-phase and 2-phase carbon materials as well as 3-phase hybrid carbon materials. The 3-phase hybrid carbon materials composed of metal nanoparticles, carbon nanotubes and graphene can be used as a promising EMI shielding material.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.4
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• pp.324-327
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• 2019

This study analyzes the low-frequency magnetic shielding effectiveness (SE) of a metal plate, in terms of diffusion and slot effects, by conducting a numerical simulation and implementing an analytical solution. When the metal has a low conductivity, the SE is dominated by the diffusion effect. However, when the conductivity and frequency both increase, the slot has a major influence on the SE. These results can be used as guidelines in the shielding design and SE requirements of electromagnetic pulse protection facilities.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.67-68
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• 2021

Social infrastructure facilities can be destroyed instantly when exposed to EMP (ElectroMagnetic Pulse), causing social chaos. However, concrete structures with low electrical conductivity cannot expect EMP shielding effect. Therefore, in this study, a metal sprayed thin film showing excellent EMP shielding performance was applied to a concrete structure to evaluate the metal spray welding efficiency and adhesion performance of the thin film according to the concrete surface treatment method. As a result according to the concrete surface treatment method, It was confirmed that the use of a roughening agent that generates physical irregularities in order to improve the welding efficiency and adhesion performance increases the physical performance of the concrete and metal sprayed thin film.

• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.430-434
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• 2010

The sheet for electromagenetic interference (EMI) shielding was prepared with slurry made by the mixture of binder, methyl ethyl ketone, cyclohexanone and metal powder. We tried to enhance the shielding efficiency by adding carbon nanotube (CNT), which has known as highly conducting material. Surface and component analyses were carried out with SEM and EDS, respectively. The electric characteristics and EMI shielding efficiencies were measured with 4-point probe measurement and EMI efficiency measurement equipment. The sheet with 2% CNT addition showed the lowest electrical resistance, $13.13{\Omega}}{\cdot}cm$. It also showed the highest EMI shielding efficiency of 63 dB.

• Textile Coloration and Finishing
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• v.10 no.2
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• pp.8-17
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• 1998

In this study we have examined electroless chemical plating on the plasma grafted poly [ethylene terephathalate］(PET) fabric in order to improve the interfacial adhesion between metal and fiber. The vapour phase of acrylic acid introduced on the PET surface and the graft polymerization was carried out by using cold plasma, resulting in the grafting yield of 0.8-1.3 wt％. The carboxyl group of the plasma grafted was identified by FT-IR-ATR spectra. The Interfacial adhesion was related to the carboxyl group. After electroless chemical plating of nickel, it showed that the more the carboxyl, the better the interfacial adhesion. Comparing to the untreated, the plasma grafted fabric showed fairly good interfacial adhesion(5B grade, ASTM D3359) . The shielding effect of electromagnetic wave showed 95dB. The shielding effect depends on the fabric structure, the surface structure, and the cross sectional shape of fibers. The dense fabric structure, the etched surface like a microcrater, and the trigonal cross sectional shape were prefered.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.243-244
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• 2011

In general, magnetite or barite (density: more than 4.0ton/㎥) has been used in concrete for radiation shielding, and radiation tests have been performed to evaluate shielding performance. However, researchers have not studied concrete for radiation shielding that utilizes electric arc furnace oxidizing slag. This research aims to utilize electric arc furnace oxidizing slag which depends on reclamation as environment-friendly concrete materials by using coarse and fine aggregates of electric arc furnace slag containing 30% ferrous metal and with a density of around 3.0~3.8 ton/㎥. Accordingly, this research has judged that the high density electric arc furnace oxidizing slag aggregate can be applied to radiation shielding concrete. It has also examined the possibility of developing radiation shielding concrete utilizing electric arc furnace oxidizing slag aggregate by comparing concrete utilizing all fine and coarse aggregate of electric arc furnace oxidizing slag with concrete using magnetite.

• Korean Journal of Materials Research
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• v.16 no.5
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• pp.285-291
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• 2006

Copper powders have been widely used in electrically conductive coatings, electrode materials et al. and are very prospective since they are cheaper than noble metal powders such as silver or palladium. In this study, copper powders for metal filler of EMI shielding have been prepared using a solvothermal process from $CuSO_4$, NaOH, Glucose, mixed solvent ($H_2O$: Ethanol) and hydrazine which was used as a reducing agent at various reaction conditions. The prepared copper powders showed finely dispersed spherical shape without agglomerate, uniform morphology, narrow size distribution, high purity and were about 400-700 nm in size. The prepared powders were characterized using XRD, SEM, TGA, XPS, particle size measurement and EMI shielding efficiency.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1544-1551
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• 2024

A unique brick series based on Vietnamese clay was manufactured at 114.22 MPa pressure rate for γ-ray attenuation purposes, consisting of (x) metallic waste & (90%-x) red clay mineral & 10% (hardener mixed with epoxy resin), where (x) is equal to the values 0%, 20%, 40%, 50%, and 70%. The impacts of industrial metal waste ratio in the structure and radiation protective characteristics were evaluated experimentally. The increase in metallic waste doping concentrations from 0% to 70% was associated with an increase in the manufactured brick's density (ρ) from 2.103 to 2.256 g/cm³ while the fabricated samples' porosity (Φ) decreased from 11.7 to 1.0%, respectively. Together with a rise in fabricated brick's density and a decrease in their porosities, the manufactured bricks' γ-ray attenuation capacities improved. The measured linear attenuation coefficient (μ, cm^-1) was improved by 30.8%, 22.1%, 21.6%, and 19.7%, at E_γ equal to the values respectively 0.662, 1.173, 1.252, and 1.332 MeV, when the metallic waste concentration increased from 0% to 70%, respectively. The study demonstrates that manufactured bricks exhibit superior radiation shielding properties, with radiation protection efficiencies of 88.4%, 90.0%, 91.7%, 92.1%, and 92.4% for bricks with industrial metal waste contents of 0%, 20%, 40%, 50%, and 70%, respectively, at γ-ray energy (E_γ) of 1.332 MeV.